The preparation and characterization of nano-sized Pt-Pd/C catalysts and comparison of their superior catalytic activities for methanol and ethanol oxidation

2012-12-01
Ozturk, Zafer
Sen, Fatih
Sen, Selda
Gökağaç Arslan, Gülsün
In this study, two groups of carbon supported PtPd samples with different percentages of metals were prepared to examine the effects of Pd and stabilizing agents on the catalytic activity towards methanol and ethanol oxidation reactions. As a stabilizing agent, 1-hexanethiol and 1,1-dimethyl hexanethiol were used for group "a" and "b" catalysts, respectively. Cyclic voltammetry, chronoamperometry, X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy (XPS) were employed to understand the nature of the prepared catalysts. TEM and XRD results indicated a similar size distribution of the metal nanoparticles with a narrow average crystallite size of 3.0-3.7 nm. XPS data revealed the presence of two different oxidation states for both platinum and palladium, being Pt(0), Pt(IV), Pd(0), and Pd(II). Electrochemical studies indicated that the group "b" type catalysts have a higher catalytic activity than group "a". The most active catalyst was found to be a carbon supported 88 %Pt/12 %Pd prepared with 1,1-dimethyl hexanethiol, which has an activity of similar to 5 times (similar to 0.450 A/mg Pt at 0.57 V for methanol) and similar to 14 times (similar to 0.350 A/g Pt at 0.56 V for ethanol) greater than the commercial E-TEK catalyst.
JOURNAL OF MATERIALS SCIENCE

Suggestions

On the Structure Sensitivity of CO Oxidation on Alumina Supported Pd-Pt Bimetallic Catalysts
Kaya, Sarp; Erunal, Ebru; Shaltaf, Riad; Ellialtıoğlu, Süleyman Şinasi; Üner, Deniz (2009-01-01)
CO oxidation reaction was studied over monometallic and bimetallic palladium-platinum catalysts at 25:75, 50:50, and 75:25 Pd:Pt atomic fractions co-impregnated over a gamma-Al2O3 support. The size of the metal particles, measured by modified hydrogen chemisorption, increased as the Pd fractions in the catalyst increased. The surface compositions and site metal distributions of the catalysts determined from Monte Carlo simulations indicated that Pd atoms segregated to the surface: at low Pd levels, Pd occup...
An investigation of the microstructural and mechanical properties of tri-calcium phosphates doped with aluminum and fluoride ions
Tahmasebifar, Aydin; Evis, Zafer; Department of Engineering Sciences (2011)
The aim of this study was to investigate the microstructure and mechanical properties of pure tricalcium phosphate (TCP) and tricalcium phosphates doped with aluminum (Al3+) and fluoride (F-) ions at different compositions. TCP was synthesized via precipitation method and sintered at 1100C for 1 and 5 h. It was observed that density and relative density of the sintered materials were decreased by extending the sintering time. Increased densities were achieved upon Al3+ and/or F- doping. For structural anal...
The preparation and characterization of gold(0) nanoclusters stabilized by zeolite framework: Highly active, selective and reusable catalyst in aerobic oxidation of benzyl alcohol
Zahmakiran, Mehmet; Özkar, Saim (2010-05-15)
Zeolite framework stabilized gold(0) nanoclusters were prepared by the ion-exchange/impregnation of Au3+ ions with zeolite-Y followed by reduction of the Au3+ ions using sodium borohydride in aqueous solution, all at 50 degrees C. The zeolite framework stabilized gold(0) nanoclusters were isolated as red powder and characterized by HR-TEM, TEM, TEM-EDX, XRD, XPS, DR-UV-vis, SEM, ICP-OES spectroscopic methods and N-2-adsorption technique. This new material was found to be highly active, selective and reusabl...
The effect of H2:N2ratio on the NH3synthesis rate and on process economics over the Co3Mo3N catalyst
Hargreaves, Justin S.J.; Aslan, Melis; Üner, Deniz (2021-02-01)
In this study, the process economics of ammonia synthesis over Co3Mo3N was investigated by searching for an optimum feed stoichiometry. From ammonia synthesis rate measurements at atmospheric pressure and 400 °C over Co3Mo3N, it was found that the rate was independent of H2: N2 stoichiometry for stoichiometries above 0.5: 1. For H2: N2 stoichiometries below 0.5: 1, there was a linear dependency of ammonia synthesis rate on the H2: N2 stoichiometry. Static measurements of hydrogen adsorption isotherms at 25,...
The effects of metallic catalysts on light crude oil oxidation in limestone medium
Celebioglu, D; Bağcı, Ali Suat (2002-08-20)
In this study, 28 experiments were performed to study the effects of metallic additives on light crude oil oxidation in limestone medium. Karakus and Beykan crude oils from Turkish oil fields were used. The metallic additives were ferric chloride (FeCl3) copper chloride (CuCl) and magnesium chloride (MgCl(2)(.)6H(2)O). The mixture of aqueous solutions of three metallic salts with limestone and the crude oils was subjected to a controlled heating schedule under a constant flow rate of air. The produced gas w...
Citation Formats
Z. Ozturk, F. Sen, S. Sen, and G. Gökağaç Arslan, “The preparation and characterization of nano-sized Pt-Pd/C catalysts and comparison of their superior catalytic activities for methanol and ethanol oxidation,” JOURNAL OF MATERIALS SCIENCE, pp. 8134–8144, 2012, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/35653.